Hydrogenation thermodynamics of melt-spun magnesium rich Mg-Ni nanocrystalline alloys with the addition of multiwalled carbon nanotubes and TiF₃

Based on the complexity of hydrogen absorption/desorption process and from the perspective of overall control, the as-cast Mg-10wt%Ni (Mg10Ni) alloy has been successively optimized by melt-spinning and surface catalyzed to realize the internal refinement as well as surface modification. The isothermal hydrogenation behavior of modified Mg-rich alloys has been investigated in this work. The results indicate that melt-spun Mg10Ni catalyzed by multiwalled carbon nanotubes (MWCNTs) coupling with TiF₃ possesses superior activation properties and can absorb 6.23 wt% at 250°C under 2.5 MPa. It is worth mentioning that the hydrogenation capacities of Mg10Ni-MWCNTs-TiF₃ are 5.93 wt% and 5.99 wt% within the initial 1 min and 5 min, respectively. Meanwhile, the catalytic effect of MWCNTs and TiF₃ has been discussed. The improved activation performance as well as the thermodynamics properties of Mg10Ni catalyzed by MWCNTs and TiF₃ is attributed to the synergistic effect on dissociation of H₂ molecules, diffusion of H-atoms and heterogeneous nucleation of hydrides.